Metal-working machine



Dec, 30, 1924.

B. M. w. HANSON METAL wonxme. momma Filed Oct. 6, 192; 1:5 Sheets-Sheet;1

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B. M. W. HANSON METAL WORKING MACHINE Filed Oct. 6, 1921 13 Sheets-Sheet8 Dec, 30, 1924. 1,520,712

a. M. w. HANSON METAL WORKING MACHINE Filed Oct. 6, 1921 13 Sheets-Sheet9 abhor/nag Deg,

B. M. W. HANSON METAL WORKING MACHINE Filed Oct. 6, 1921 15 Sheets-Sheetl0 Fiied Oct. 6, 192

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. B. M. w. HANSON METAL WORKING MACHINE Filed 001;. 6, 1921 13Sheets-Sheet l2 lllllli Dec. 1924- 1,520,712

B. M. W. HANSON METAL WORKING MACHINE Filed 001:. 6, 1921 13Sheets-Sheet 15 Patented Dec. 30, 1924.

PATENT tliFFi-CE.

BENGT l JL W. HANSON, F HARTFORD. CONNECTICUT.

METAL-WORKING MACHINE.

Application filed October 6, 1921.

To all whom it may concern:

Be it known that 1, Elmer M. W. HAN- soN, a citizen of the UnitedStates, and a resident of Hartford, county of Hartford, State ofConnecticut, have invented certain new and useful Improvements in aMetal- YVorlring, Machine, of which the following is a specification.

This invention relates to improvements in metal working machines. Thevarious features of the present invention will be described witheference to their use in the particular machine here selected for thepurpose of illustration and which is a machine for threading cylindricalmembers.

The object of the invention is to provide 1 a machine of the characterdescribed having various features of novelty and advantage and which isparticularly characterized by its accuracy and efiiciency in operation.In accordance with this invention, provisions are made for accuratelysetting and adjusting the members relative to one another andautomatically controlling the movements thereof so that they may performtheir various functions with precision and expedition.

The present machine is peculiarly adapted for use in threadingcylindrical members and applied to this use has a very wide anduniversal application in that either eX- ternal or internal threads maybe formed on various sizes of work of different materials with facilityand accuracy. If desired, the vmachine may be readily adjusted tooperate first on one piece of work carried by one spindle and then asecond piece of work car- .ried by another spindle, or to operate on thework carried by both of these spindles simultaneously.

I desire it to be clearly understood that the present disclosure is byway of exemplilication only, that the invention is susceptible ofvarious embodiments and modifications, and that the terms here used aremerely terms of description and not in any sense terms of limitation. Itwill further be obvious that many features of the construction aresusceptible of modification to suit dii'l'erent requirements withoutdeparting from the spirit of the invention.

In the accompanying drawings Fig. 1 is a top plan view of the entiremachine,

Fig. 2 is a rear view thereof,

' the adjustable work Serial No. 505,864.

Fig. 3 is a partial view in elevation of that end of the machine whichcarries the tappet wheel for controlling the movements of certain of theparts,

Fig. 1 is a sectional view taken substantially on line s- 1 of Fig. 1and looking in the direction of the arrows,

Fig. 5 is a detail view taken substantially on line 55 of Fig; 4, i

Fig. 5 a detail view taken substantially on line 5*-5 of Fig. 1, andillustrates the manner in which the adjusting screw for the cross slideis fixed against longitudinal movement relative thereto,

Fig. 6 is a view taken longitudinally and centrally through the workspindle,

Fig. 'l' is a section taken substantially on line 7-7 Fig. 1 and shows,in part, the mechanism through which the work spindleis rotated,

Fig. 8 is a view in horizontal section of one form of a tool head,

Fig. 9 is a view similar to Fig. 8 but shows a slightly diiferentconstruction,

Fig. 10 is a view in horizontal section taken substantially on lines1010 of 7 and 11., and shows, in part, the mechanism through which thework spindle and other parts of the machine are driven and controlled.

Fig. 11 is a transverse section taken on line 11-11 of Fig. 10,

Fig. 12 is an enlarged detail View of the mechanism for disconnectingand connecting the work spindle to the driving mecha nism,

Fig. 13 is a view showing oiagrammatically the relation of the tappetwheel and the cams used where a single work spindle is employed,

Fig. 14 is a plan view showing the machine equipped with a pair of workspindles,

Fig. 15 is a vertical sectional view taken on line 15-15 of Fig. 1-4:,

Fig. 16 is a front view, that is looking in the direction. of the arrow16 of Fig. 14, of

spindle.

Fig. 17 is a vertical sectional view taken on line 17-17 of Fig. 14,

Fig. 18 is a view similar to Fig. 13, but shows the a rangeinent andrelation of the tappet wheel and cams where two Worli spindles and twotools are employed and the tools are adapted to alternately cooperatewith the respective pieces of work carried by thespindles, I

Fig. 19 is a view showing the construction of the cam for moving thetool carriage longitudinally where the tools are to operatesimultaneously upon the respective pieces of work carried by the twospindles,

Figs. 20 and 21 show the direction of rotation of the tool and spindlesfor internal and external threading, respectively,

Fig. 22 is a view showing the extent to which a tapered hob is movedlongitudinally by the pitch portion of the cam r to cut a. taper.thread,

Fig. 23 is an exaggerated view showing diagrammatically the extent towhich the tapered hob is moved radially into the work during the cuttingoperation by the earn 8. Ashereinafter described more in detail, themachine here selected for illustrative purposes is provided with twowork spindles,'OI h,of which is removable so that'the machine maybeoperated with but one work spindle or with both work spindles, asdesired. For convenience in description, the arrangement andconstruction of the parts and the operation of the machine will first betakenup where: a single spindle is employed. Then the machine willbedescribed where both 'of the spindles are used.

Referring to Figures 1 to '3', the general arran ement and or 'anizationof the ar-incipal parts of the machine, can be easily seen. (an is apedestal or base of any suitable construction on one end of whlch ismounted a fixedhousing b rotatably supporting a workspindle-(2.,(seeFig. 6), provided with a collet mechanism d for holdingthe work. Slidably mounted upon ways 6 extending longitudinally ofthebase is a tool carrier or movable support comprising a main carriage fofsomewhat T-shape and a cross slide 9 mounted for reciprocation on thetransverse stem 7? of the-carriage andcarrying a head it for the tool orhob indicated by the letter 2'. This-slide 9 may be manually adjustedonthe carriage 7, by turning the shaft 70.. The hob irls driven from themam shaft Z through transmission gearing in the box 121..

and the driving connections shown mos. clearlyin Fig. l. The. worksplndle c is driven through the transmission gearing within theboxes. mand n and thedriving connections shown most clearly in Figs. 7, 9

' and 10. The change of speedofrotation of the work spindle is effectedthrough suitable by a cam o" rotatably mountedinthc based,

The transverse. movement ofthe slide 9 is. brought about by a earn .9rotatablymounttappet Wheel 0 are all driven' from the work spindle as ishereinafter described.

In order that the detailed descriptions of the construction of themachine and its mode of operation, which are to follow, maybe betterunderstood, a very brief statement of the general eperationofthemachine, where a single work spindle is employed, will be given here.The threading tool or hob i is. continuously driven at a selected. speedof rotation depending, for instance, on the kind. of material to beoperated upon. The work spindle 0, while the tool is being moved upto'and out of operative relation'to the work,

is driven at a relatively fast rate of speed, I

and during the threading operation the work spindle is driven. at aselected slow rateof speed depending, for instance, on the di- Now.

ameter of the piece to be threaded. after the work has been positionedin the work spindle c and the power tllIKOWIiOIltO this spindle, thespindle, together withthe tappet wheel 0 and the cams 1" and s driventherefrom, are rotated at-a relatively fast rate of speed; the cam 0quickly moves the tool carrier, as a whole in a direction longicarriagef is moved slowly by. the cam r in a direction longitudinally of thetool in accordance with the. desired pitch of the thread to be cut andthe cross slide 9 is movedto feedthe tool into. the work to the requireddepth of the thr ad. Thereafter, the cross sllde 9 remains stationary onthe main carriage f while the latter continues. its slow movement adistance equal tothe desired pitch of the thread during which-time thework makes one complete revolution. ll lien the threading operation iscompleted, a second tappct will .11 throw the clutch resulting in arapid rotation of the spindle, the

tappet wheel and thecams 1", s; the cam s.

will withdraw. preferablyat a fast rate of speed, the tool. from the worand then the cam will move the tool carriage longitudinally back intoinoperative position. I able mechani m, controlled by thedog wheel. isprovided for automatically stopping the parts at the end of the sequenceofoperations to allow the completed piece of worr to be withdrawn fromthe'work spindle-and a new piece insertedin its, place.

From the foregoing description, it will be seen that sincetheca-msm ands areidriven from the work spindle, the ratio of'the I ed in thecarriage f. v The cams r and s and the speeds of rotation between thespindle and the cams remains constant regardless of changes of speed ofthe spindle. Therefore, it the cam 7' has been so adjusted to more thetool longitudinally during the cutting operation at a speed which willgive a given pitch of thread on a piece of work of one diameter, thissame adjustment or setting may be used for cutting a like pitch onpieces of work of lesser or greater diameters. For the purpose ofchanging from one pitch to another the cam r is provided with aplurality oi interchangeable inserts or pitch blocks, one for eachpitch. The arrange ment is further such that the extent or distancewhich the cross slide is moved by the cam s to bring the tool radiallyup to the worlr and then feed the tool into the were: to

the (.esired depth, is constant, but the speed at which this cross slidemoves to that extent is variable tie desired vanations in speed being;brought about by properly adjusting the tappcts on the tappet wheel. Thereason tor this la terarra genient that where a thread ot' desiredpitch, for instance 8 pitch, is to be operated upon, the cross slide inder to save time is moved for the greater portion of its stroke at arapid rate of speed and is then moved slowly-for only a small portion ofits stroke, corresponding to the depth of the thread to be cut. i herethread ct larger pitch, for instance 4 pitch, is to be cut. the toolmust enter into the worlr twice the depth required for the 8 pitchthreau; therefore the cross slide is moved slowly a distance twice asgreat as that required in the previous instance.

Referring now to the detail construction of the machine the arrangementoi the tool carrier and the tool head, and the manner in which the toolis driven will first be described. Adjustably mounted on the under sideof the head or longitudinally extending part oi the carriage is a barcarrying at its forward end a follower or roller 26 worls inn; in thecam groove of the cam r, as shown in Fig. (5. Adjustment of the carriagerelative to this bar is brought about by manually turning; a knurledhead 27 which, through suitable pinions 28, rotates a pinion 9 9jouii'naled in the carriage f and meshing with the rack 30 on the sideof the bar as shown most clearly in Figs. 1 and 4:. ihe carriage f thebar are clamped to- L;r,bl11' in any desired position of adjustment byturning the handle 31. The purpose ot' providing the adjustable bar 25on the tool carrier is to permit of longitudinal adjust ment ot thetool. in accordance with the extent to which the part of the work to bethreaded projects beyond the work spindle c.

The cross slide 9 carries on its under face. as shown in Figs. 4 and 5,a nut provided with a follower or roller 36 which works in the grooveoi": the cam s fixed to a pin 3 through a depending h journaled insuitable hearings 38 depending from the main carriage. In the presentinstance, the nut block comprises two parts 35, 35 adapted to be clampedto a dove-tail gib ll on the under side of the cross slide by a clampingbolt 42 which extends through an elongated slot 43 in the sine of themain carriage f. It screw as most clearly shown in Figs. 4, 5 and 5 isin threaded engagement wits the bl cl; extends r? on the cross slide andis fin d against longitudinal move ment relative thereto by theabutments or collars 4:8; and carries its rear end a bevel gear -6meshing with like gear on, the rear end of the shaft All which isjournaled in suitanle bearings on the slide.

It will be seen that the extent of throw of the slide g, as effected bythe earn a, is

constant. To adjust the tool radially of the work spindle and thus talzecare oi pieces of work of? ditlerent diameters and different pitches,the nut is loosened from the .y'

of the slide, and the shaft .l: is then sally rotated to turn the screw4-4 re in moving the slide longitudinally o. nut which is heldstationary by the cam a. The nut is then clamped to the gib 41 byturning; up the bolt 42. The extent to which the shaft is moved may bedetermined on the dial d9.

The tool heads shown in Figs. 0 and 5) are generally similar inconstruction. In each case, the head includes a body portion or castingin which journaled atool spindle 51 carrying at its forward end the hobThe forward end ot the tool sniu dle may be supported in a bee. j bralrel' 53 which is to removed when the hob is to cut an internal thread.The tool head is pivoted by stud to the cross slide, 5 and may beangularly adjusted by a set screw F5 carried by the body portion 5H andengaging against an abut sent on the cross slide 9. The head is securedto the cross slide 9 in adjusted position by means of screws 57 passing;throng) i OUGlLfiIjS in the head which are slightly r than shanis o1.the screws to permit 0'! the angular ad ustment of the head. 'i -sprovision for angularly adjustirn the head may be used to advantage insetting the tool so that the line of contact between the tool and thework will be parallel to the axis ot the work. This setting of the toolsis frequently necessary because, in hardening the tools. they oftentalro ntl tapered form.

In the embodiment shown in 8. the tool spindle carries a bevel gear 59with which meshes a bevel gea (Ellen .l shaft (ill journaled at itsforward end in suitable bearings 62 in the body portion and having;splincd to its rear end the bevel gear 63. shown in lfig. l. In theembodiment shown in hi 9, the bevel gear 59 is fixed to stock 67.

anintermediate shaft 64 which'is connected up through gearing 65: tothetool spindle.

6G denotes' a flywheel. Either of the tool heads illustrated may be usedfor both external and internal threading. I The head shown in Fig.Qisused where a long piece of work'is to be operated upon and supportedat its outer end by the The shaft. 61 is provided with a flexible1011117 68 which is in 'ert1cal alinein-ent with the stud so as topermit of angular adjustment of the tool head. The bevel gear 63 is,rotatahly n'munted in a housing 69 mounted on the rear end: of the stemor leg 7" of 'the'main carriage f. Meshing with the gear 63. is a hevelgear 70- c'arried by a vertical shaiit'i'1inounted in the carriage f andcarrying at its lower end a gear 72' with which meshes a bevel gear 73splined moved into and out of clamping; engagement with the work byalongitudinally movable tube operahlethrough the levers 81. and

sleeve 82 by the yoke 88 and handle 84;..as is. usual. As shown in Fig.7, the work spindle a is provided with a worm wheel 85 with which meshesa worm 86 on a drive shaft 87 provided at its forward end with adetachable crank handle 88. interposed in the drive shaft is a clutch89. which may he either automatically or manually thrown out to stoprotation of the spindle without throwing the power oil" of the gearingthroughwhich the spindle is driven. On the rear end of the drive shaft87 is; a re versing clutch including a pair of opposed bevel gears 90loose on the shaft 87, and clutch sleeve 91 fixed to the shaftandadapted to he moved into and out of clutching en.- .Q'agement withthe clutch teeth on the respective gears 90 by means oi a yoke 92'fixed'to a shaft 93 carrying an operating handle 941-. Meshing with the gears90- anddriving them in opposite directions is a bevel gear fixed on theupper end of a vertical shaft 90 provided at its lower end with anoverrunning or one-way clutch u through which the work spindle is-drivenat a relatively low selected speed. This clutch, whieh is or a well.known type, includesa worm wheel loose on the shaft 96, and a disk 101last on that shaft and carrying, as shown in Figs. 7" and 10; a link 102and a frictionshoe 103'. The arrangement of this 05 clutch is such thatwhen the shatt 96 and ad'iustahle tai l The selected speed at which thedisk 101 are drivenat a greater speed than theworniwheel, the'shoe willride-free of the latter, but when-theshaft is not driven ata greater:speed,.. thev shoe iswedged against the worm wheel causing. the wormwheel and the: shaft. to rotate together.

This shaft 96 is' alsoprovided' with aclutch o comprising, a sleeve 106loose on-the shalt. 96 and a slidahle sleeve 107 keyed to the shaft.

106 hyan escapemen-t clutch 10 the opera tion of "which is controlledby, the tap-pet wheel 0-, as hereinafter descrihed more in detail.

Fixed to theloose sleeve 1060f the-clutch o is a he'vel gear 110 whichis constantly driven at a.- un'torm rastra-te' o t' rotation as- 10, 11)meshing with a large gear 113 on an intermediate shaft 114 carrying afixed bevel gear 115 meshing with the gear 110 which, as stated, isfixed. tothe clutch sleeve- In the present illustrative disclosure,

106. the gear 113 firms a partot'. "a? friction clutch, 1t beingnormally held in frictionalengagement with a. stepped gear 116 fixedtothe shaft 11% by means of a spring pressed sleeve 117 splinedoirtheshaft 114. This sleeve 117 may be withdrawn from frictional engagementwith the gear 113 by a handle 118 working through a yoke 119. Thisclutch is thrown out when it is desired to shift the gears within thetransmission loci:

The worm gear 1000f theclutch u is-con-- stantly rotated at any desiredsingle speed within a given range of: selected speeds in the following;manner: Fixed to the shaft 11 1 is the cone or steppedgear. 110inesl-iing with a. plurality gears-12%loose on shaft 12 1-. The gears198 are selectively fixed to the shaft 124.- hy a. pawl 12-5 con- Thesleeve 107 is movedyintoz and out, 0t clutching; engagement with thesleevenected to rod 126 longitudinally slidahle within the shaft 124;-and' having, a. racy 19;? with which meshes aitoothed disk. 128 ac ed tobe rotated by turning; a. handle 12 Spline-d on the shaft 124: arealarg'e ge and a small gear1132 adapted tobe sh dhv means of fork 133and. handle- 13 1. The gears-131' 132 are arranged-to; mesh respectivelywith a small'gear: 135 and a largie gear 136 on a 'wormshaft- 137.O-n-ther 1 it. is'a worm 138 in-mesh-with the-worm: wheel 100 of the.clutch m.

It will be seen that with thearrangement iring; described, the-gear 110rand-c utch she e106 are continuously rotated-at a uni:- form speedthrough the: shatt 111,.inter1neshing gears 112, 1'13; shaft 11% andbevelagear 115. The selected spee at which the tool spindle is to bedriven is obtained by swinging the handle 129 to fix the proper gear 123on the shaft 124; and moving the handle to shift the gears 131, 132. Thedrive of the worm wheel of the clutch u is through the constantly drivenstepped gears 116, the gears 123 which are selectively liTECd to theshaft 12 1, the intermening gears 131, (or 132, 136 as the case may be),the shaft 137 and the worm 138.

For the purpose of preventing shifting of the gears when the pow-er ison, that is while the friction clutch of which the gear 113 forms a partis engaged, the following arrangement is provided: Extending from thehandle portion 134 is a segment 1&0 provided with a pair of notches 1 11in which is adapted to engage a finger 1 -2 carried by the handle 118 bywhich the clutch 113 is operated. (in the outer end of the shaft 1 13,which carries the toothed member 12, a notched plate 1-14 and in thenotches of this plate one end of a longitudinally movable rod is adaptedto engage. The other end of this rod engages against the outer end ofthe handle 118 which is provided w'th a notch 1 16. in. Fig. 1, thelever 118 for the friction clutchis shown in that position when theclutch is in. In this position, it will be seen that the finger 142engages in one of the notches 141, thus preventing operation of thehandl 13%. The outer end of the handle 118 prevents withdrawal of therod i l-.5 from one of the notches of the plate so that this latterplate together with the too lied member 128 cannot be turned. When thehandle 118 moved into position to dis engage the friction clutch, thefinger 1 is withdrawn from the notches 1-11 perm of operation of thehandle 13- and the notch 1-16 is brought into registry with the rodpermitting the latter to be moved out 11H) of the notch in the plate 114, thus allowing this plate, together with the parts cot nectedthereto, to be operated.

The drive of the tappet u el 0 and the cams 7" and s from the workspindle is follows: Referring to Figs. and 6, it will be seen thatfitted to the spindle 0, within a casing 1&5, is a gear 116 with whichmeshes either a small ar 14:7 or a large gear 1 18. Fixed to the gear14-8 a pinion 149 meshing with a gear 150 tired 1 the shaft 151 whichcarries tie cam 2". .d to the shaft 151 is a gear 152 meshing with a 153on the tappet wheel shaft 15 1. This tappet wheel shaft 154: carries, asshown in Fig. at, a bevel gear 155 meshing with a like ar on therotatable stud 37 which carries @1116 cam s, as heretofore statedv It ispre "able that the spindle be driven in one dii ion wncn an externalthread is being); cut and in the reverse direction when an internalthread is being cut, in order that-the parts of the tool carrier besecurely held to their seats. This will be clearly understood uponreference to Figs. 20 and 21 where the hob i is shown as rotating in thesame direction for both internal and external threading while the piecesof work W rotate in opposite directions. In both instances, the tool isforced downwardly so that the tool head, the cross slide and thecarriage are pressed against each other and the carriage is securelyheld to its on the base a of the machine, and thus there is no playbetween or vibration of these parts. If the hob 2' and the work wererotated in the direction of the dotted arrows of Fig. 21, the tendencywould be to raise the hob and the parts supporting the same, leading toinaccuracies, undesin able strains, and looseness and play between theparts. The change in the direction of rotation of the spindle iseli'ected, as here tofore stated, through the reversing clutch whichincludes the gears 90. The tappet wheel and the cams, however, arerotatable in one direction only in accomplishing their functions, andtherefore when the direction of rotation of the spindle is chanced, itIS necessary to change the gearing between the tappet wheel and thespindle so that the former will not change its direction of rotation. Tothis end, the large gear 148 and the small gear 147, which are in meshwith each other, are carried by a rocker 157 in such manner that eitherof the gears 1&8 or 14-7 may be thrown into mesh with the gear 146.

The clutch 0) which, as stated, when in engagement results in drivingthe work spindle and cams at a fast rate of speed, is controlled throughthe escapeinent ratchet clutch mechanism to by the tappet wheel 0 in thefollowing manner: Fixed on a freely rotatable shaft within the casing 02(see Figs. 7 and 10) is a ratchet 166 and a gear 167, the latter beingin mesh with a gear 168 integral with the gear 110 which, as previouslystated, is fixed to the loose clutch sleeve 106 of the clutch e. As thegear 168 is constantly driven, the gear 167, together withthe shaft 165and the ratchet wheel 166, is constantly rotated. Loose upon the shaft165 is a cam 169 which, upon rotation, shifts a shipper lever 170 tomove the clutch sleeve 107 up and down on the shaft 96 and therebyengage and disengage the clutch o. Fixed to, so as to r0 tate with, thecam 169 is disk 172 carrying a spring pressed pawl 173, periodicengagement of which with the constantly ro tating ratchet wheel 166 iscontrolled by an escapement yoke 174: having diametrically oppositestops 175 adapted to be alternately brought into the path of travel ofthe pawl 173 so that the earn 169 is intermittently rotated throughangles of The escapement yoke 174: is fixed t0q so as to move with, arod 1'77 slida'hly supported in hearings 178 in the casing n. The outerend of the rod 12''? carries a grooved collar 179 which receives theyoke end of a lever lSOpii' o ted at 181 as shown in Figs. 1 and Theopposite end of the lever 180 is hingedlv connected, as at 182 to a pin183 slidably mounted in a hearing 18 t. The free end of this pin 183carries a tappet 185 with which the tappets 187 of the tappet wheel areadapted to cooperate. In the present instance, there are two suchtappets 18"? one on each side of the tappet wheel.

The active faces of these tappets are inclined, as at 188, so that oneof the ta'ppets will throw the pm 183 in one direction to disconnect theclutch o and the other tappet designated for convenience by 18?) willthrow the pin 183 in the opposite direction to engage the c'li'itch o.These tappets are adjustable angularl v oit the tappet able sleeve 19'?of the clutch 89, this clutch,

as stated, being interposed in the drive shaft 8? hetween theworkspindle and the power 7 I The 1ever 195 1s iiior nallv urgedin adirect on operated means for driving the same.

to hold the clutch 89 engaged lov' spring pressed plunger 198. Mountedin the free .end of the lever 195 is a spring 'ii'essed pin 199, theouter end of which projects into the path of inove nent oft a tappet 200adjustably mounted on the tappet wheel 0.

l Vhenthe tappet 200, which 1110 785 in the direction the arrow Fig. 12engages the pm 199'; the lever 195 is rotated counterclockwise and aspring pressed latch 201 carried by the lever engages a catch 202 tohold the clutchse' disengaged. The latch is released from the catch andthe plunger or pin 1% is withdrawn from the. path of the tappet 200 bypushing in a rod 203 having an inclined nortiou204 which wipes against astud 20'5dcarried by the pin 199' and engaglng' against the. tail end ofthe latch 201. Diseng geinent ot' the clutch 89 may-he manually effectedat any tiine by V pulling out the rod 203, to bring a shoulde'r 206thereon into "engagement with the stud 205 which results in swinging"the lever 19 5 to a position where the latch engages the catch 202. Therear corner of the ra per: 200 is cutaway or relieved as which to eachother and the tappet vwheel 0' i will be most clearly understo'oc'l byrefer ence to Fig. The earns rotate in the direction of the arrow shownon the earn 0". The cam groove of the cam 1* has an inclined portion210, which is operative to advance the tool cail'rier longitudinally upto the work; a pitch portion 211, which is operative to feed the toollongitudinally in accordance with the desired pitch to he cut; a returninclined portion. 212, which is operative to withdraw the toollongitudinally back into inoperative position, and a short inactiveportion 213 in which the follower 26 connected to the tool carriage fengages when the 091111 1" is automatically stopped. The pitch portion211 of the can'r groove is provided with a removable block 214. Therewill he as many of these interchangeable pitch blocks as there aredifferent pitches of thread to he cut, wi'thin the capacity or" themachine. 7 hese pitch blocks constitute means for varying the extent 01throw of the cams. Theinclination of the grooves in these blocks willvarv, of course, in accordance with the desired longiti'ic'li-' nal feedof the tool that block shown in Fig. 13, being employed for cutting aright handed thread of maximum pitch. The dotted lines 211 on, thisblock 214] indicates the inclination'ot the groove in that insertibleblock which IS '8 TlplO* '6(l for ("jutting a left handed thread of mairnuni pitch. it will be seen that the portion 210 and the cam groovesof the several 'pitcl'i blocks accurately register. The forward end ofthe return inclined portion 212 is or increased width, as at 215, so astoperinit the follower 26 to rideout of any one of the pitch groovesinto the return groove portion 212. 1

The groove in the cam s hasan inactive portion 217 in which the follower36 engages while the work carriage is being moved longitudiiiallv up toand away irom' the work bv the cam r: a short inclined portion 219 whichfeeds the tool laterall up to and into the work: a short inactiveportion 219 in which the follower 36 rides during the threadingoperation: and a short return incl ned portion 220 which moves the toollaterallv out of engagement with the work.

For the purpose of catching oil which inav flow through the openingsinthe top of theloase a. there are tirovided on the inside wallsv of thebase upwardly inclined flanges 225 forming oil receiving channels 226which communicate through ports-227 with the channels 228 the externalWall lot;

